U.S. patent application number 13/025953 was filed with the patent office on 2011-10-06 for polyamide molding materials reinforced with glass fibers and injection molded parts thereof.
This patent application is currently assigned to EMS-CHEMIE AG. Invention is credited to Volker Eichhorn, Ornulf Rexin, Georg STOEPPELMANN.
Application Number | 20110240930 13/025953 |
Document ID | / |
Family ID | 44708555 |
Filed Date | 2011-10-06 |
United States Patent
Application |
20110240930 |
Kind Code |
A1 |
STOEPPELMANN; Georg ; et
al. |
October 6, 2011 |
POLYAMIDE MOLDING MATERIALS REINFORCED WITH GLASS FIBERS AND
INJECTION MOLDED PARTS THEREOF
Abstract
The present invention relates to reinforced polyamide molding
materials with high notch impact strengths, comprising low viscous
polyamides and flat glass fibers as a reinforcing medium,
characterized in a polyamide matrix, comprising the following
components: (A) 0 to 60 wt.-% of at least one aliphatic, partly
crystalline polyamide with a solution viscosity, measured in
m-cresol (0.5 wt-%), of .eta..sub.rel less than 1.9, (B) 0 to 60
wt.-% of at least one amorphous or microcrystalline polyamide based
on aliphatic, cycloaliphatic or aromatic diamines, dicarboxylic
acids, lactams and/or aminocarboxylic acids, preferably with 6 to
36 carbon atoms, or a mixture of such homopolyamides and/or
copolyamides, wherein the components (A) and (B) fulfill the
condition: (A)+(B)=20 to 60 wt.-% and that, in the case of a
mixture of components (A) and (B), at least 50 weight parts
aliphatic blocks (A) are present in the mixture, and a filler
component, comprising: (C) 40 to 80 wt.-% flat glass fibers with
elongated shape, and the glass fibers have a non-circular
cross-sectional area and a size ratio of the main cross-sectional
axis to the secondary cross-sectional axis of between 2 to 5,
particularly between 3 and 4, and (D) 0 to 40 wt.-% particle like
or layer like fillers, with the prerequisite that carbon fibers are
excluded, wherein the polyamide molding materials optionally
comprise up to 5 wt.-% of further usual additives and auxiliary
agents (E), and wherein the weight of the components (A) to (E)
sums up to 100%.
Inventors: |
STOEPPELMANN; Georg;
(Bonaduz, CH) ; Rexin; Ornulf; (Heidelberg,
DE) ; Eichhorn; Volker; (Chur, CH) |
Assignee: |
EMS-CHEMIE AG
Domat/EMS
CH
|
Family ID: |
44708555 |
Appl. No.: |
13/025953 |
Filed: |
February 11, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11966688 |
Dec 28, 2007 |
|
|
|
13025953 |
|
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|
Current U.S.
Class: |
252/511 ;
252/500; 264/328.1; 264/500; 524/492; 524/494; 977/742;
977/773 |
Current CPC
Class: |
C08L 77/00 20130101;
C08L 77/06 20130101; C08L 77/02 20130101; C08K 7/14 20130101; C08L
2205/16 20130101; C08L 77/02 20130101; C08L 77/06 20130101; C08K
7/14 20130101; C08K 7/14 20130101; C08L 2666/20 20130101; C08L
77/06 20130101; C08L 77/00 20130101; C08K 3/40 20130101; C08L
2205/02 20130101; C08L 77/06 20130101 |
Class at
Publication: |
252/511 ;
524/494; 524/492; 252/500; 264/328.1; 264/500; 977/773;
977/742 |
International
Class: |
H01B 1/24 20060101
H01B001/24; C08K 3/40 20060101 C08K003/40; C08L 77/06 20060101
C08L077/06; H01B 1/20 20060101 H01B001/20; B29C 45/00 20060101
B29C045/00; B29C 49/00 20060101 B29C049/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2006 |
EP |
06 027 036.0 |
Claims
1. Reinforced polyamide molding materials with high notch impact
strength, comprising low viscous polyamides and flat glass fibers
as a reinforcing medium, comprising a polyamide matrix, comprising
the following components: (A) 0 to 60 wt.-% of at least one
aliphatic, partly crystalline polyamide with a solution viscosity
.eta..sub.rel, measured in m-cresol (0.5 wt-%), of less than 1.9,
(B) 0 to 60 wt.-% of at least one amorphous or microcrystalline
polyamide based on aliphatic, cycloaliphatic or aromatic diamines,
dicarboxylic acids, lactams and/or aminocarboxylic acids, with 6 to
36 carbon atoms, or a mixture of such homopolyamides and/or
copolyamides, with a solution viscosity .eta..sub.rel, measured in
m-cresol (0.5 wt-%), of less than 1.9, wherein the components (A)
and (B) fulfil the condition: (A)+(B)=20 to 60 wt.-% and that, in
the case of a mixture of components (A) and (B), at least 50 weight
parts aliphatic blocks (A) are present in the mixture, and a filler
component, comprising: (C) 40 to 80 wt.-% flat glass fibers with
elongated shape, and the glass fibers have a non-circular
cross-sectional area and a size ratio of the main cross-sectional
axis to the secondary cross-sectional axis of between 2 to 5,
preferably between 3 and 4, and (D) 0 to 40 wt.-% particle like or
layer like fillers, with the proviso that carbon fibers are
excluded, wherein the polyamide molding materials optionally
comprise up to 5 wt.-% of further usual additives and auxiliary
agents (E), and wherein the weight of the components (A) to (E)
sums up to 100%.
2. Reinforced polyamide molding materials with a high notch impact
strength, comprising low viscous polyamides and flat glass fibers
as a reinforcing medium, comprising a polyamide matrix, comprising
the following components: (A) 20 to 60% by weight of at least one
aliphatic, partly crystalline polyamide with a solution viscosity
.eta..sub.rel, measured in m-cresol (0.5 wt-%), of less than 1.9,
(B) 0 to 50% by weight, preferably 0 to 20 wt.-%, more preferably 0
to 15 wt.-%, of at least one amorphous or microcrystalline
polyamides based on aliphatic, cycloaliphatic or aromatic diamines,
dicarboxylic acids, lactams, and/or aminocarboxylic acids, with 6
to 36 carbon atoms, or a mixture of such Homo polyamides and/or
copolyamides, with a solution viscosity .eta..sub.rel, measured in
m-cresol (0.5 wt-%), of less than 1.9, with the prerequisite that
in the case of a mixture of components (A) and (B), at least 50
weight parts aliphatic blocks (A) are present in the mixture, and a
filler component, comprising: (C) 40 to 80 wt.-% flat glass fibers
with elongated shape, and the glass fibers have a non-circular
cross-sectional area and a size ratio of the main cross-sectional
axis to the secondary cross-sectional axis of between 2 to 5,
preferably between 3 and 4, and (D) 0 to 40 wt.-% particle like or
layer like fillers, with the prerequisite that carbon fibers are
excluded, wherein the polyamide molding materials optionally
comprise up to 5 wt.-% of further usual additives and adjuvants
(E), and wherein the weight of the components (A) to (E) sums up to
100%.
3. Polyamide molding materials according to claim 1, wherein the
flat glass fibers have the form of cut glass with a length of 2 to
50 mm.
4. Polyamide molding materials according to claim 1, wherein the
flat glass fibers are in amounts of between 50 and 70 wt.-% in the
molding materials.
5. Polyamide molding materials according to claim 1, wherein the
flat glass fibers, which are added as chopped glass strands, have a
diameter of the main cross-sectional axis of 6 to 40 .mu.m and a
diameter of the secondary cross-sectional axis from 3 to 20 .mu.m,
wherein the ratio of the perpendicular cross-sectional axes is
between 2 and 5.
6. Polyamide molding materials according to claim 1, wherein the
flat glass fibers are selected from E glass fibers, A glass fibers,
C glass fibers, D glass fibers, M glass fibers, S glass fibers or R
glass fibers or mixtures thereof.
7. Polyamide molding materials according to claim 1, wherein at
least one aliphatic, partly crystalline polyamide of component (A)
has a solution viscosity .eta..sub.rel, measured in m-cresol (0.5
wt.-%), of .eta..sub.rel less than 1.8.
8. Polyamide molding materials according to claim 1, wherein at
least one aliphatic, partially from polyamide of component (A) is
selected from the group, consisting of polyamide 6, polyamide 46,
polyamide 66, polyamide 11, polyamide 12, polyamide 1212, polyamide
1010, polyamide 1012, polyamide 1112, polyamide 610, polyamide 612,
polyamide 69, polyamide 810 or their mixtures, blends or
alloys.
9. Polyamide molding materials according to claim 1, wherein the at
least one microcrystalline or amorphous polyamide is selected from
the group of homopolyamides and/or copolyamides based on PA 6I, PA
6I/6T, PA MXDI/6I, PA MXDI/MXDT/6I/6T, PA MXDI/12I, PA MXDI, PA
MACM 9-18, PA MACMI/12, PA MACMI/MACMT/12, PA6I/MACMI/12, PA
6I/6T/MACMI/MACMT, PA 6I/6T/MACMI/MACMT/12, PA MACM6/11, PA
MACMI/MACM12, wherein MACM may be replaced by PACM by more than 55
mol-%.
10. Polyamide molding materials according to claim 1, wherein the
molding materials have notch impact strengths of at least 30
kJ/m.sup.2 (measured according to Charpy at 23.degree. C. according
to ISO 179/2-1 eA) at a glass fiber percentage .gtoreq.60 wt.-% or
a notch impact strength of more than 25 kJ/m.sup.2 (measured
according to Charpy at 23.degree. C. according to ISO 179/2-1 eA)
at a glass fiber percentage of 50 to 60 wt.-%.
11. Polyamide molding materials according to claim 1, characterized
in a high flow length, for thin-walled injection-molded parts made
from the molding materials, of >200 mm at reinforcing levels
with component (C) of over 40 wt.-%.
12. Polyamide molding materials according to claim 1, wherein
further additives and adjuvants (E) in the molding material are
selected from the group of inorganic stabilizers, organic
stabilizers, lubricants, dyes, metallic pigments, metal gewgaw,
metal coated particles, halogen-containing flame retardants,
halogen-free flame retardants, impact modifiers, antistatics,
conductivity additives, mold releasing agents, optical brighteners,
natural sheet silicates, synthetic sheet silicates or mixtures of
the above additives.
13. Process for the preparation of polyamide molding materials
according to claim 1, using usual compounding machines at barrel
temperatures set to 240.degree. C. to 320.degree. C., wherein
firstly the polymeric part is molten and then cut flat glass fibers
and/or other fillers are added.
14. Process for the preparation of polyamide molding materials
according to claim 1, wherein firstly a compound is respectively
produced from the components (A) and/or (B) and the fillers (C) and
optionally (D) and optionally the additives (E) in granular form
and then these granules are mixed, and then further quantities of
granules of the components (A) and (B) are optionally added, and
then the granules are processed.
15. Process for the production of molded parts from the polyamide
molding materials according to claim 1, by injection molding,
extrusion, pultrusion, blow molding or other molding
techniques.
16. Molded part obtainable from the polyamide molding materials
according to claim 1.
17. Molded part according to claim 17, wherein it is a mobile phone
housing or a mobile phone housing part.
18. In a method for the manufacture of molded parts, comprising
molding such a part by injection molding with a reinforced
polyamide molding material, the improvement being that said
reinforced polyamide molding material comprises the reinforced
polyamide molding material of claim 1 having a notch impact
strength of more than 25 kJ/m.sup.2 (measured according to Charpy
at 23.degree. C., according to ISO 179/2-1 eA).
19. Polyamide molding materials according to claim 1, wherein the
flat glass fibers, which are added as chopped glass strands, have a
diameter of the main cross-sectional axis of 6 to 40 .mu.m and a
diameter of the secondary cross-sectional axis from 3 to 20 .mu.m,
wherein the ratio of the perpendicular cross-sectional axes is
between 3 and 4.
20. Polyamide molding materials according to claim 1, wherein the
flat glass fibers are selected from E glass fibers, A glass fibers,
C glass fibers, D glass fibers, M glass fibers, S glass fibers or R
glass fibers or mixtures thereof, wherein E glass fibers are
preferred, and wherein the fibers have an amino coating or epoxy
silane coating.
21. Polyamide molding materials according to claim 1, wherein the
at least one aliphatic, partly crystalline polyamide of component
(A) has a solution viscosity .eta..sub.rel, measured in m-cresol
(0.5 wt.-%), of .eta..sub.rel less than 1.7.
22. Polyamide molding materials according to claim 1, wherein the
at least one at least one amorphous or microcrystalline polyamide
of component (B) has a solution viscosity .eta..sub.rel, measured
in m-cresol (0.5 wt.-%), of .eta..sub.rel less than 1.7.
23. Polyamide molding materials according to claim 1, wherein at
least one aliphatic, partly crystalline polyamide of component (A)
has a solution viscosity .eta..sub.rel, measured in m-cresol (0.5
wt.-%), of .eta..sub.rel of more than 1.3 to less than 1.9 and/or
the at least one amorphous or microcrystalline polyamide of
component (B) has a solution viscosity .eta..sub.rel, measured in
m-cresol (0.5 wt.-%), of .eta..sub.rel of 1.5 to 1.7.
24. Polyamide molding materials according to claim 1, wherein at
least one aliphatic, partly crystalline polyamide of component (A)
has a solution viscosity .eta..sub.rel, measured in m-cresol (0.5
wt.-%), of .eta..sub.rel of more than 1.35 to less than 1.9.
25. Polyamide molding materials according to claim 1, wherein at
least one aliphatic, partly crystalline polyamide of component (A)
has a solution viscosity .eta..sub.rel, measured in m-cresol (0.5
wt.-%), of .eta..sub.rel of 1.6 to 1.9.
26. Polyamide molding materials according to claim 1, wherein the
at least one microcrystalline or amorphous polyamide is PA
6I/6T.
27. Polyamide molding materials according to claim 1, wherein
further usual additives and adjuvants (E) in the molding material
are selected from the group of conductivity additives, selected
from the group of carbon black and/or carbon nanotubes.
28. Injection molded part, obtainable from the polyamide molding
materials according to claim 1
29. Polyamide molding materials according to claim 1, wherein the
component (A) is selected from the group consisting of Polyamide
66, Polyamide 1010, Polyamide 12 or mixtures thereof.
30. Polyamide molding materials according to claim 1, wherein the
polyamide components (A) and/or (B) both have a numerical average
molecular weight of more than 10,000 g/mol and of less than 20,000
g/mol.
31. Polyamide molding materials according to claim 1, wherein the
molding material is adapted to and capable of providing thin-walled
injection moulded parts having a flow length of greater than 200
mm.
32. Reinforced polyamide molding materials with high notch impact
strength made on a compounding machine, comprising low viscous
polyamides and flat glass fibers as a reinforcing medium,
comprising a polyamide matrix, comprising the following components:
(A) 0 to 60 wt.-% of at least one partly crystalline polyamide
selected from the group consisting of Polyamide 66, Polyamide 1010,
Polyamide 12 or mixtures thereof with a solution viscosity
.eta..sub.rel, measured in m-cresol (0.5 wt-%), of more than 1.3
and of less than 1.9, (B) 0 to 60 wt.-% of at least one amorphous
polyamide selected from the group consisting of PA 6I/6T, PA MACM
9-18 or mixtures thereof with a solution viscosity .eta..sub.rel,
measured in m-cresol (0.5 wt-%), of more than 1.3 and of less than
1.9, wherein the polyamide components of said reinforced polyamide
molding material consist of components (A) and (B) and wherein the
polyamide components (A) and (B) both have a numerical average
molecular weight of more than 10,000 g/mol and of less than 20,000
g/mol, wherein the components (A) and (B) fulfil the condition:
(A)+(B)=20 to 60 wt.-% and wherein, in the case of a mixture of
components (A) and (B), at least 50 weight parts aliphatic blocks
(A) are present in the mixture, and a filler component, comprising:
(C) 40 to 80 wt.-% flat glass fibers with elongated shape, and the
glass fibers have a non-circular cross-sectional area and a size
ratio of the main cross-sectional axis to the secondary
cross-sectional axis of between 2 to 5, preferably between 3 and 4,
and (D) 0 to 40 wt.-% particle like or layer like fillers, with the
proviso that carbon fibers are excluded, wherein the polyamide
molding materials optionally comprise up to 5 wt.-% of further
additives and auxiliary agents (E), and wherein the weight of the
components (A) to (E) sums up to 100% and wherein said molding
material is adapted to and capable of providing thin-walled
injection moulded parts having a flow length of greater than 200
mm.
33. Reinforced polyamide molding materials with high notch impact
strength made on a compounding machine, comprising low viscous
polyamides and flat glass fibers as a reinforcing medium,
comprising a polyamide matrix, comprising the following components:
(A) 20 to 60 wt.-% of at least one partly crystalline polyamide
selected from the group consisting of Polyamide 66, Polyamide 1010,
Polyamide 12 or mixtures thereof with a solution viscosity
.eta..sub.rel, measured in m-cresol (0.5 wt-%), of more than 1.3
and of less than 1.9, (B) 0 to 60 wt.-% of at least one amorphous
polyamide selected from the group consisting of PA 6I/6T, PA MACM
9-18 or mixtures thereof with a solution viscosity .eta..sub.rel,
measured in m-cresol (0.5 wt-%), of more than 1.3 and of less than
1.9, wherein the polyamide components of said reinforced polyamide
molding material consist of components (A) and (B) and wherein the
polyamide components (A) and (B) both have a numerical average
molecular weight of more than 10,000 g/mol and of less than 20,000
g/mol, wherein the components (A) and (B) fulfil the condition:
(A)+(B)=20 to 60 wt.-% and wherein, in the case of a mixture of
components (A) and (B), at least 50 weight parts aliphatic blocks
(A) are present in the mixture, and a filler component, comprising:
(C) 40 to 80 wt.-% flat glass fibers with elongated shape, and the
glass fibers have a non-circular cross-sectional area and a size
ratio of the main cross-sectional axis to the secondary
cross-sectional axis of between 2 to 5, preferably between 3 and 4,
and (D) 0 to 40 wt.-% particle fillers or layer fillers, with the
proviso that carbon fibers are excluded, wherein the polyamide
molding materials optionally comprise up to 5 wt.-% of further
usual additives and auxiliary agents (E), and wherein the weight of
the components (A) to (E) sums up to 100% and wherein said molding
material is adapted to and capable of providing thin-walled
injection moulded parts having a flow length of greater than 200
mm.
Description
CROSS-REFERENCED TO RELATED APPLICATIONS
[0001] This application is a continuation in part of Ser. No.
11/966,688, filed Dec. 28, 2007, the entire contents of which are
hereby incorporated by reference.
FIELD OF INVENTION
[0002] The present invention relates to reinforced polyamide
molding materials comprising low viscous polyamides and glass
fibers with flat shape, especially glass fibers with non-circular
cross-sectional area and a dimensional relation of the main
cross-sectional axis to the secondary cross-sectional axis of
between 2 and 5. The present invention further relates to a process
for the production of polyamide molding materials, as well as
molded parts made thereof, i.e. in particular injection molded
parts.
[0003] According to the invention a polyamide with a solution
viscosity of .eta..sub.rel less than 1.9 (measured in m-cresole,
0.5 wt.-%, 20.degree. C.) is regarded as a low viscous polyamide.
The relative viscosity of .eta..sub.rel less than 1.9 corresponds
to a molecular weight (M.sub.n, numerical average) of the
polyamides of less than 20,000 g/mol.
BACKGROUND OF THE INVENTION
[0004] Reinforced polyamides are playing an increasing role in the
field of technical construction materials, since they have high
rigidity, high toughness and high heat distortion temperature.
Fields of application are, for example, internal and external parts
in the automotive sector and in the field of other means of
transport, housing material for appliances and equipment for
telecommunication, consumer electronics, household appliances,
machinery equipment, apparatus in the field of heating and fixing
parts for installation. Metal like properties are important for
parts, for example, in the automotive sector, but these can only be
achieved by highly filled, reinforced molding materials. For
thin-walled parts, particularly a high flow length of the molding
materials is necessary, which flow length, however cannot or can
only very poorly be achieved in molding materials that are
reinforced by endless fibers.
[0005] There is also a special advantage of reinforced polyamides
in the exceptionally good bonding between polymer matrix and
reinforcing materials. This is true even at high reinforcement
levels, resulting in products with high tensile modulus of
elasticity. However, the toughness of the products is not
sufficient to fulfil all requirements.
[0006] Polymers which are regarded as polyamides in the present
invention that have basic building blocks, which are held together
by amide bonds (--NH--CO--), and which can be prepared by
polycondensation or polymerization of monomers, as for example
dicarboxylic acids, dicarboxylic acid halides, dinitriles,
diamines, aminocarboxylic acids and/or lactames. They can be
homopolyamides or copolyamides. The average molecular weight of the
polyamide should be more than 5,000, preferably more than 10,000
but less than 20,000, corresponding to solution viscosities of
.eta..sub.rel lower than 1.9, especially .eta..sub.rel lower than
1.8, particularly preferred .eta..sub.rel lower than 1.7.
[0007] EP 0 190 011 B1 describes glass fibers with elliptical or
rectangular cross-section, as well as their manufacture. The use of
these particular glass fibers for the manufacture of composite
parts is mentioned. Due to the larger surface of the fibers, higher
strength values result in the composites.
[0008] EP 0 196 194 B1 describes a strand consisting of a variety
of glass monofilaments with a non-circular cross-section, as well
as their manufacture. The cross-section of the glass fibers can be
oval, elliptical, cocoon shaped or polygonal.
[0009] EP 0 199 328 B1 describes a fabric for printed circuit
boards, which is essentially made of glass fibers with non-circular
cross-section. The individual fibers have oval, elongated or
elliptical cross sections. Unsaturated polyester resins, epoxy
resins, phenol resins, polyimide resins or PTFE are described as
matrices for this fabric.
[0010] EP 0 246 620 B1 describes an article made of a glass fiber
reinforced thermoplastic resin. The, glass fibers have a
rectangular, elliptical or cocoon shaped cross section. It is shown
that glass fibers with non-circular cross-section have advantages
in terms of strength and toughness, especially at a high degree of
reinforcement (.gtoreq.60%).
[0011] EP 0 376 616 B1 describes a thermoplastic polymer
composition comprising a thermoplastic resin and 1 to 65% of a
fibre like reinforcement with a non-circular cross-section, wherein
the cross-sectional area and the ratio of the perpendicular
cross-sections of the reinforcing fibers are characterized in more
detail. The cross-section of the reinforcing fibers has a
semicircular or arcuate contour. The composition is characterized
by high dimensional stability and reduced warpage.
[0012] EP 0 400 935 B1 describes a flame retardant fiber reinforced
polyester composition that includes 1 to 60 wt % glass fibers.
According to EP 0 400 935 B1, the used glass fibers have a
cross-sectional shape, which is selected from the group of
flattened, elliptical, oval, partly circular, curved and
rectangular cross-sectional shapes. These flame retardant
reinforced polyester composites according to EP 0 400 935 B1 show a
decreased deformation without their mechanical properties being
adversely influenced by crystalline polyester resins. In this
respect, it was found according to EP 0 400 935 B1 that the
deformation, i.e. warping of crystalline polyester resins can be
reduced without reducing the mechanical properties of the resin,
for example, the bending strength and rigidity and the
processability.
[0013] According to JP 10219026 A2 the thermoplastic matrix is
reinforced by a mixture of glass fibers with a circular
cross-section and glass fibers with a flat cross section to reduce
warpage of thermoplastic parts. Polyamide 66 is used as a polymer
matrix in the only example of this document.
[0014] JP 2004285487 A1 describes a bundle of glass fibers,
consisting of glass filaments with a flat cross-section, which are
hold together by a non-volatile sizing, and a thermoplastic
composition, consisting of 5 to 75% of glass fiber bundles and a
polyolefin matrix.
[0015] JP 2006045390 A2 describes a granulate reinforced by long
glass fibers, consisting of a thermoplastic matrix and up to 60
wt.-% of glass fibers with a flat cross section. Granulate length
and fiber length is identical. Advantageous features of molded
parts made from the reinforced composition according to JP
2006045390 A2 are good surface quality and high impact
strength.
[0016] Polyamide molding materials, which have good mechanical
properties and a very small warpage, are described in the still
unpublished patent application EP 06014372.4. These properties are
obtained by a combination of transparent polyamide with fibrous
reinforcing materials and particulate fillers. Regarding the
fibrous reinforcement materials there are basically no
restrictions. They are preferably selected from the group
consisting of glass fibers, carbon fibers, metal fibers, aramide
fibers, whiskers and mixtures thereof. The glass fibers can be
added as endless fibers or as chopped glass fibers. The glass
fibers can have round, oval or rectangular cross section.
[0017] The also still unpublished application EP 05025216.2
describes reinforced polyamide molding materials made from a blend
of polyamide 66 and a copolyamide 6T/6I. A mixture of glass fibers
and carbon fibers is used as a reinforcing material. To further
increase the rigidity, a portion of the glass fibers is substituted
by carbon fibers, so that a hybrid fiber reinforced compound is
used.
SUMMARY OF THE INVENTION
[0018] It is therefore an object of the present invention to
provide new reinforced polyamide molding materials based on low
viscosity polyamides, i.e. having molecular weights (M.sub.n) of
less than 20,000 g/mol, which are clearly superior to the molding
materials with glass fibers with a circular cross-section in terms
of mechanical properties and processing properties. The molded
parts made from the molding materials should also have high
transversal rigidity and transversal resistance.
[0019] The above object is achieved by the polyamide molding
materials according to claim 1, the process according to claim 13,
the use according to claim 15, the process for manufacturing the
molded bodies according to claim 16, and the molded article,
especially the injection-molded article according to claim 17.
[0020] The objects of the invention are achieved by providing
reinforced polyamide molding materials with high notch impact
strength, comprising low viscous polyamides and flat glass fibers
as a reinforcing medium, comprising a polyamide matrix, comprising
the following components:
(A) 0 to 60 wt.-% of at least one aliphatic, partly crystalline
polyamide with a solution viscosity .eta..sub.rel, measured in
m-cresol (0.5 wt-%), of less than 1.9, (B) 0 to 60 wt.-% of at
least one amorphous or microcrystalline polyamide based on
aliphatic, cycloaliphatic or aromatic diamines, dicarboxylic acids,
lactams and/or aminocarboxylic acids, with 6 to 36 carbon atoms, or
a mixture of such homopolyamides and/or copolyamides, with a
solution viscosity .eta..sub.rel, measured in m-cresol (0.5 wt-%),
of less than 1.9, [0021] wherein the components (A) and (B) fulfil
the condition:
[0021] (A)+(B)=20 to 60 wt.-% [0022] and that, in the case of a
mixture of components (A) and (B), at least 50 weight parts
aliphatic blocks (A) are present in the mixture, and [0023] a
filler component, comprising: (C) 40 to 80 wt.-% flat glass fibers
with elongated shape, and the glass fibers have a non-circular
cross-sectional area and a size ratio of the main cross-sectional
axis to the secondary cross-sectional axis of between 2 to 5,
preferably between 3 and 4, and (D) 0 to 40 wt.-% particle like or
layer like fillers, [0024] with the proviso that carbon fibers are
excluded, wherein the polyamide molding materials optionally
comprise up to 5 wt.-% of further usual additives and auxiliary
agents (E), and [0025] wherein the weight of the components (A) to
(E) sums up to 100%.
[0026] The process for producing the reinforced polyamide molding
materials involves using conventional compounding machines at
barrel temperatures set to 240.degree. C. to 320.degree. C.,
wherein the polymeric part is first melted and then cut flat glass
fibers and/or other fillers are added to the molten polyamide.
[0027] Molded parts from the polyamide molding materials are
produced by injection molding, extrusion, pultrusion, blow molding
or other molding techniques.
[0028] Therefore, in embodiment (I) the invention relates to
reinforced polyamide molding materials with high notch impact
strength, comprising low viscosity polyamides and flat glass fibers
as a reinforcing medium, comprising a polyamide matrix, comprising
the following components: (A) up to 60 wt.-%, particularly from 20
to 60 wt.-%, of at least one aliphatic, partly crystalline
polyamide with a solution viscosity, measured in m-cresol (0.5
wt.-%), of .eta..sub.rel less than 1.9, as well as a filler
component comprising (C) 40 to 80 wt.-% flat glass fibers with
elongated shape, wherein the glass fibers have a non-circular
cross-sectional area and a size ratio of the main cross-sectional
axis to the secondary cross-sectional axis of between 2 to 5,
especially between 3 and 4, and optionally (D) up to 40 wt.-%
particle like or layer like fillers, and optionally up to 5 wt.-%
further usual additives and auxiliary agents (E), wherein the
weight percents of the components (A), (C) and optionally (D) and
(E) sum up to 100 wt.-%, with the prerequisite that carbon fibers
are excluded.
[0029] Generally speaking, the solution viscosity .eta..sub.rel,
measured in m-cresol (0.5 wt-%), of component (A) is preferably in
the range of more than 1.3 to less than 1.9, preferably of more
than 1.35 to less than 1.9, and more preferably of more than 1.4 to
less than 1.9, most preferred is the range of 1.6-1.9.
[0030] In an alternative embodiment (II), the present invention
relates to reinforced polyamide molding compounds with high notch
impact strength, comprising low-viscous polyamides and flat glass
fibers as reinforcing medium, comprising a polyamide matrix,
comprising up to 60 wt.-%, particularly from 20 to 60 wt.-%, of at
least one aliphatic, partly crystalline polyamide (B) with a
solution viscosity, measured in m-cresol (0.5 wt.-%), of
.eta..sub.rel less than 1.9, as well as a filler component
comprising (C) 40 to 80 wt.-% flat glass fibers with elongated
shape, wherein the glass fibers has a non-circular cross-sectional
area and a size ratio of the main cross-sectional axis to the
secondary cross-sectional axis of between 2 to 5, especially
between 3 and 4, and optionally (D) particle like or layer like
fillers, and optionally usual additives and auxiliary agents (E),
with the prerequisite that carbon fibers are excluded, wherein the
weight percents of the components (B), (C) and optionally (D) and
(E) sum up to 100 wt.-%.
[0031] Generally speaking, the solution viscosity .eta..sub.rel,
measured in m-cresol (0.5 wt-%), of component (B) is preferably in
the range of more than 1.3 to less than 1.9, preferably of more
than 1.35 to less than 1.9, and more preferably of more than 1.4 to
less than 1.8, most preferred is the range of 1.5-1.7.
[0032] In another embodiment (III) of the present invention, it
relates to reinforced polyamide molding material with high notch
impact strength, comprising low viscosity polyamides and flat glass
fibers as a reinforcing medium, comprising a polyamide matrix,
comprising the following components: [0033] (A) up to 60 wt.-%,
particularly from 20 to 60 wt.-%, of at least one aliphatic, partly
crystalline polyamide with a solution viscosity, measured in
m-cresol (0.5 wt-%), of .eta..sub.rel less than 1.9, [0034] (B) up
to 60 wt.-% of at least one amorphous or microcrystalline polyamide
based on aliphatic, cycloaliphatic or aromatic diamines,
dicarboxylic acids, lactams and/or aminocarboxylic acids,
preferably with 6 to 36 carbon atoms, or a mixture of such
homopolyamides and/or copolyamides, [0035] wherein the components
(A) and (B) fulfil the condition:
[0035] (A)+(B)=20 to 60 wt.-% [0036] and that there are at least 50
weight parts of aliphatic blocks (A) present in the mixture (of the
components (A) and (B)), and [0037] a filler component, comprising:
[0038] (C) 40 to 80 wt-% flat glass fibers with elongated shape,
wherein the glass fibers have a non-circular cross-sectional area
and a size ratio of the main cross-sectional axis to the secondary
cross-sectional axis of between 2 to 5, especially between 3 and 4
have, and optionally [0039] (D) 0 to 40 wt-% particle like or layer
like fillers, and [0040] (E) conventional additives and auxiliary
agents. [0041] wherein the weight percents of the components (A) to
(E) sum up to 100%, with the prerequisite that carbon and carbon
fibers are excluded.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 shows an injection molded body for warpage
measurement. Warpage is determined at this injection molded body
according to FIG. 1. The sprue is made from the bottom in z
direction.
[0043] FIG. 2 shows the location of the measurement points in the
injection molded body in x direction for warpage measurements;
[0044] FIG. 3 shows the location of the measurement points in the
injection molded body in z direction for warpage measurements;
[0045] FIG. 4 shows the warpage of the measurement points 7 to 9
(see FIG. 2) in x direction;
[0046] FIG. 5 shows the warpage of the measurement points 10 to 12
in x-direction;
[0047] FIG. 6 shows the warpage of the measurement points 13 to 15
in z direction;
[0048] FIG. 7 shows the warpage of the measurement points 19 to 21
in z direction.
DETAILED DESCRIPTION OF THE INVENTION
[0049] According to the invention it has been found that flat glass
fibers (ratio of the cross-sectional axes >2) show significant
advantages in the mechanical properties, processing and surface
quality compared to those with circular cross-section. This is
particularly true for high glass fiber contents of >50%. Thus,
in inventive polyamide molding materials, particularly for example,
in PA12 with 65 wt.-% glass fibers with otherwise same formulation,
twice as high notch impact strength has been found using flat glass
fibers when compared to glass fibers with a circular geometry.
These high toughness values are also found, if an inventive
polyamide molding material, particularly a PA12 with lower
molecular weight, is used. A PA12 with lower molecular weight has a
low melt viscosity. Therefore, it has advantages in the injection
molding process.
[0050] Usually lower toughness values are found in polyamides with
low molecular weights than in those with higher molecular weights.
However, at high filling levels the thermoplastic processing is
complicated due to higher viscosity of the higher molecular
polyamides. This manifests in difficult form filling, sink marks
and poor surface quality.
[0051] According to the invention it has been further found that,
especially for high percentages of flat glass fibers, products can
be made, which have good processability, low warpage, high surface
quality and substantially higher toughness compared to those
materials, which contain glass fibers that have a circular
cross-section, when using the inventive molding materials,
preferably with the low viscous, aliphatic partly crystalline
polyamides, more preferably with low viscous PA12.
[0052] Compared to glass fibers with a circular cross-section,
glass fibers with a cross-section with different values for the
main axis and the secondary axis (flat glass fibers) have a
significantly higher packing density at high levels of
reinforcement, which results in higher moduli and strength,
especially transverse to the fiber orientation. However, the
expected improvement in rigidity and strength is only completely
realized, if the rather smaller spaces between the flat glass
fibers are sufficiently infiltrated with polymer matrix, and the
matrix allows sufficient forwarding of the forces occurring during
deformation. Only the polyamides with low viscosity according to
the invention make full use of the potential of geometrically
advantageous flat glass fibers.
[0053] Especially components which are under pressure during use,
as for example valve housings or water meter housings, benefit from
the increased rigidity and strength traverse to the fiber
orientation, because burst pressure and deformation resistance are
improved among others. Due to the higher transverse rigidity of
components made from the inventive molding materials, which is 10
to 40% above the level of molding compounds with glass fibers with
circular cross-section, depending on the composition, there are
significantly fewer deformations of the component under varying
pressure loads. This is of particular interest, because molding
compounds based on aliphatic polyamides with usual glass fibers of
circular cross-section often show low transverse rigidity compared
to the longitudinal rigidity. This shortcoming can be offset by
using flat glass fibers in combination with polyamides, since not
only the individual values for the longitudinal and transverse
rigidity are increased, but also the ratio of transverse to
longitudinal rigidity.
[0054] The matrix of polyamide molding materials, which is used
according to the invention, is based, as described above, on at
least one aliphatic, partly crystalline polyamide (component (A))
or at least one amorphous and microcrystalline polyamide (component
B), or a mixture of components A and B, wherein at least 50
wt.-parts aliphatic components (A) must be present in the mixture
of (A) and (B).
[0055] The aliphatic, partly crystalline polyamide (component (A))
has a solution viscosity, measured in m-cresol (0.5 wt-%), of
.eta..sub.rel less than 1.9, preferably by .eta..sub.rel less than
1.8, particularly .eta..sub.rel less than 1.7. A polyamide from the
group consisting of polyamide 6, polyamide 46, polyamide 66,
polyamide 11, polyamide 12, polyamide 1212, polyamide 1010,
polyamide 1012, polyamide 1112, Polyamide 610, polyamide 612,
polyamide 69, polyamide 810 or their mixtures, blends or alloys may
be used as an aliphatic polyamide.
[0056] In a particular embodiment of the invention, at least two
aliphatic polyamides with different solution viscosities are used
together with the other components. For instance, a PA12 with a
solution viscosity in the range from 1.45 to 1.67 and a PA12 with a
solution viscosity in the range from 1.75 to 1.9 are mixed, wherein
the mixing ratio of low and higher viscous PA12 is between 80:20
and 20:80.
[0057] In an alternative embodiment, the polyamide molding
material, includes up to 50 wt.-%, preferably up to 20 wt.-%, more
preferably up to 15 wt.-%, of at least one amorphous or
microcrystalline polyamide (component (B)) based on aliphatic,
cycloaliphatic or aromatic diamines, dicarboxylic acids, lactams
and/or aminocarboxylic acids, preferably with 6 to 36 carbon atoms,
or a mixture of such homopolyamides and/or copolyamides in addition
to the component (A). According to this embodiment the molding
materials preferably contain 1-20 wt.-%, particularly from 3 to 15
wt.-% component (B).
[0058] The following systems are preferred for the microcrystalline
and amorphous polyamides (component (B)) and/or copolyamides used
according to the invention:
[0059] Polyamide based on aliphatic, cycloaliphatic or aromatic
diamines, dicarboxylic acids, lactams and/or aminocarboxylic acids,
preferably with 6 to 36 carbon atoms, or a mixture of such
homopolyamides and/or copolyamides. The cycloaliphatic diamines are
preferrably MACM, IPD (isophorone diamine), and/or PACM, with or
without additional substituents. The aliphatic dicarboxylic acid is
preferably an aliphatic dicarboxylic acid with 2-36, preferably
8-20, linear or branched carbon atoms, more preferably with 10, 12,
13, 14, 16 or 18 carbon atoms.
[0060] MACM stands for the ISO-name
bis-(4-amino-3-methyl-cyclohexyl)-methane, which is commercially
available under the trade name
3,3'-dimethyl-4-4'-diaminodicyclohexylmethane as Laromin C260-typ
(CAS No. 6864-37-5), preferably with a melting point between
-10.degree. C. and 0.degree. C. A number, like for example in
MACM12, stands for an aliphatic linear C12 dicarboxylic acid (DDS,
dodecanic diacid), with which the diamine MACM is
polycondensated.
[0061] IPS is isophthalic acid and PACM stands for the ISO-name
bis(4-amino-cyclohexyl)-methane, which is commercially available
under the trade name 4,4'-Diaminodicyclohexylmethane as
dicycan-type (CAS No. 1761-71-3), preferably with a melting point
of between 30.degree. C. and 45.degree. C.
[0062] A homopolyamide is preferably selected from the group,
consisting of MACM12, MACM13, MACM14, MACM16, MACM18, PACM12,
PACM13, PACM14, PACM16, PACM18 and/or a copolyamide selected from
the group MACM12/PACM12, MACM13/PACM13, MACM14/PACM14,
MACM16/PACM16, MACM18/PACM18. Mixtures of such polyamides are also
possible.
[0063] Polyamides based on aromatic dicarboxylic acids with 8 to
18, preferably 8-14 carbon atoms, or a mixture of such
homopolyamides and/or copolyamides, preferably based on PXDA and/or
MXDA, more preferably based on lactams and/or aminocarboxylic
acids, wherein the aromatic dicarboxylic acids are preferably TPS,
naphthalene dicarboxylic acid and/or IPS.
[0064] Polyamides selected from the group, consisting of MACM9-18,
PACM9-18, MACMI/12, MACMI/MACMT, MACMI/MACMT/12,
6I6T/MACMI/MACMT/12, 3-6T, 6I6T, TMDT, 6I/MACMI/MACMT,
6I/PACMI/PACMT, 6I/6T/MACMI, MACMI/MACM36, 6I, 12/PACMI or
12/MACMT, 6/PACMT, 6/6I, 6/IPDT or mixtures thereof, wherein 50
mol-% of IPS may be replaced by TPS.
[0065] These amorphous and microcrystalline polyamides (component
B) have a glass transition temperature of more than 110.degree. C.,
preferably of more than 130.degree. C. and more preferably of more
than 150.degree. C. The relative solution viscosity is in the range
from 1.4 to less than 1.9 (measured in m-cresol, 0.5% by weight,
measured at 20.degree. C.), preferably in the range between 1.5 and
1.8 and more preferably in the range between 1.55 and 1.75.
[0066] The microcrystalline polyamides have a heat of fusion in the
range of 4 to 25 J/g (determined by DSC), the amorphous polyamides
have heats of fusion of less than 4 J/g. Microcrystalline
polyamides based on the diamines MACM and PACM are preferably used.
Examples of such polyamides are the systems PA MACM9-18/PACM9-18,
wherein PA MACM12/PACM12 with a PACM percentage of more than 55
mol-% (relative to the whole amount of diamine) is particularly
used according to the invention.
[0067] Preferably, amorphous and/or microcrystalline polyamides
with a glass transition temperature of at least 130.degree. C.,
preferably at least 150 C, are used as component (B).
[0068] In another preferred embodiment microcrystalline polyamides
with a melt enthalpy of at least 4 J/g, preferably in the range of
4 to 25 J/g, are used as component (B).
[0069] The flat glass fibers used according to the invention are
glass fibers with a flat shape, and a non-circular cross-sectional
area, with the ratio of perpendicular cross-sectional axes greater
than or equal to 2, and the smaller cross-sectional axis of a
length .gtoreq.3 .mu.m. The glass fibers have the form of chopped
glass strands with a length of 2 to 50 mm. The glass fiber amount
in the molding materials according to the invention is between 40
and 80 wt.-%, preferably between 50 and 70 wt.-%. In a special
embodiment of the invention the glass fiber amount is always more
than 60 wt.-%, preferably in the range of 60-70 wt.-%.
[0070] By using chopped glass strands according to the invention
granules of long glass fiber can be excluded. Surprisingly, high
notch impact values have been achieved according to the invention,
which have otherwise only been observed for long-fiber
reinforcement and polyamides with high molecular weights and which
are here observed for chopped glass fibers. Also, the individual
filaments are not held together by any "glue" or special sizings.
According to the invention, high notch impact values, particularly
at high reinforcement values are achieved: notch impact values of
more than 25 kJ/m.sup.2 for a glass fiber percentage of 50 to 60
wt.-%, notch impacts of more than 30 kJ/m.sup.2 for a glass fiber
percentage of more than 60 wt.-%.
[0071] Furthermore high flow lengths are achieved according to the
invention, especially for the thin-walled (injection molding) parts
made from the inventive molding materials: flow lengths of >200
mm at reinforcement levels of .gtoreq.40 wt.-%. The surface quality
of the injection-molded parts made from the molding materials is
also quite excellent, as can be seen from the attached Table 1
(gloss values).
[0072] Optionally, additional fillers and reinforcing agents can be
added to the polyamide molding compounds (component (D)) in
quantities of 0 to 40 wt.-%, wherein carbon fibers are
excluded.
[0073] The molding materials according to the invention may also
include other additives (E), for example from the group of
inorganic stabilizers, organic stabilizers, lubricants, dyes,
nucleating agents, metallic pigments, metal gewgaw, metal coated
particles, halogen-comprising flame retardants, halogen-free flame
retardants, impact modifiers, antistatics conductivity additives,
mold releasing agents, optical brighteners, natural sheet
silicates, synthetic sheet silicates or mixtures of the above
additives.
[0074] For example, carbon black and/or carbon nanotubes can be
used as antistatics in the inventive molding materials.
[0075] The use of carbon black can also improve the black color of
the molding material.
[0076] For example, kaolins, serpentines, talc, mica, vermiculite,
illite, smectite, montmorillonite, hectorite, double hydroxides or
mixtures thereof may be used as sheet silicates in the inventive
molding materials. The sheet silicates may be surface treated, but
may also be untreated.
[0077] For example, antioxidants, light stabilizers, UV
stabilizers, UV absorbers, or UV-Blocker may be used as stabilizers
and aging protection products, respectively, in the inventive
molding materials.
[0078] As outlined above, the flat glass fibers (C) are added as
chopped glass strands according to the invention. These glass
fibers have a diameter of the small cross-sectional axis of 3 to 20
.mu.m and a diameter of the large cross-sectional axis of 6 to 40
.mu.m wherein the ratio of orthogonal cross-sectional axes is
between 2 and 5, preferably between 3 and 4. Particularly, E glass
fibers are used according to the invention. However, all other
glass fiber types, such as A, C, D, M, S, R glass fibers or any
mixtures thereof or mixtures with E glass fibers may be used. The
usual sizings for polyamide are used, such as various amino silane
sizings.
[0079] Specifically preferred are reinforced polyamide molding
materials with high notch impact strength made on a compounding
machine, comprising low viscosity polyamides and flat glass fibers
as a reinforcing medium, comprising a polyamide matrix, comprising
the following components:
(A) 0 to 60 wt.-% or 20-60 wt.-% of at least one partly crystalline
polyamide selected from the group consisting of Polyamide 66,
Polyamide 1010, Polyamide 12 or mixtures thereof with a solution
viscosity .eta.rel, measured in m-cresol (0.5 wt-%), of more than
1.3 and of less than 1.9, (B) 0 to 60 wt.-% of at least one
amorphous polyamide selected from the group consisting of PA 6I/6T,
PA MACM 9-18 or mixtures thereof with a solution viscosity
.eta.rel, measured in m-cresol (0.5 wt-%), of more than 1.3 and of
less than 1.9, wherein the polyamide components of said reinforced
polyamide molding material consist of components (A) and (B) and
wherein the polyamide components (A) and (B) both have a numerical
average molecular weight of more than 10,000 g/mol and of less than
20,000 g/mol, wherein the components (A) and (B) fulfil the
condition:
(A)+(B)=20 to 60 wt.-%
and wherein, in the case of a mixture of components (A) and (B), at
least 50 weight parts aliphatic blocks (A) are present in the
mixture, and a filler component, comprising: (C) 40 to 80 wt.-%
flat glass fibers with elongated shape, and the glass fibers have a
non-circular cross-sectional area and a size ratio of the main
cross-sectional axis to the secondary cross-sectional axis of
between 2 to 5, preferably between 3 and 4, and (D) 0 to 40 wt.-%
particle like or layer like fillers, with the proviso that carbon
fibers are excluded, wherein the polyamide molding materials
optionally comprise up to 5 wt.-% of further conventional additives
and auxiliary agents (E), and wherein the weight of the components
(A) to (E) sums up to 100% and wherein said molding material is
adapted to and capable of providing thin-walled injection moulded
parts having a flow length of greater than 200 mm.
[0080] The preparation of the polyamide molding materials according
to the invention can be effected on customary compounding machines,
such as, for example, single-screw or twin-screw extruders or screw
kneaders. As a rule, the polymeric fraction is first melted and the
reinforcing material (glass fibers) can be introduced at the same
point or at different points of the extruder, for example by means
of a side feeder. The compounding is preferably effected at set
barrel temperatures of 280.degree. C. to 320.degree. C. Gentler
processing of the inventive molding materials results in reinforced
molded parts, wherein the fiber length distribution is
significantly shifted to higher fiber lengths. Thus, the inventive
molding materials have an average fiber length, which is by 20 to
200% higher as compared to molded parts based on glass fibers with
a round cross-section.
[0081] The molded parts produced from the molding materials
according to the invention are used for the production of interior
and exterior parts, preferably having a supporting or mechanical
function, in the electrical, furniture, sport, mechanical
engineering, sanitary and hygiene areas, medicine, energy and drive
technology, in the automotive sector and the sector relating to
other means of transport, or housing material for devices and
apparatuses for telecommunication, entertainment electronics,
household appliances, mechanical engineering, the heating sector or
fixing parts for installations or for containers and ventilation
parts of all types.
[0082] In particular the area of metal die casting replacement in
which extremely high rigidity in combination with good toughness is
expected may be mentioned as possible applications for the molded
parts produced from the molding materials according to the
invention.
Applications
Electrical Appliance Sector
[0083] Stop and/or adjusting elements for electrical hand tools
with or without integrated electrical functions (molded
interconnect devices, MID) [0084] connecting rods and/or pistons
for hammer drills in homogenous design, i.e. comprising one
material, or as a hybrid part, i.e. comprising a combination of
materials [0085] housings, gear housings for right angle grinders,
drills, electric planes or grinding machines with or without
integrated electrical functions (MID) in homogeneous design or as a
hybrid part, certain functional areas (e.g. force transmission
surfaces, sliding surfaces, decorative layer areas, grip region)
may comprise another compatible or incompatible material (e.g. for
targeted delamination or deformation, predetermined breaking point,
force or torque limitation) [0086] tool holders, e.g. chucks or
fixing means [0087] sewing machine housings, sliding tables with or
without integrated electrical functions (MID) [0088] housings or
housing parts for telecommunication (e.g. mobile phone) and
consumer electronics
Sanitary and Hygiene Sector
[0088] [0089] Housings and/or functional elements (e.g. for pumps,
gears, valves) for oral irrigators, toothbrushes, comfort toilets,
shower cabinets, hygiene centers with or without integrated
electrical functions (MID) in homogeneous design or as a hybrid
part [0090] diverse connectors or connection modules [0091] pump
housings, valve housings or water meter housings with or without
integrated electrical functions (MID) in homogeneous design or as a
hybrid part
Household Appliance Sector
[0092] Housings and/or functional elements for mechanical,
electrical or electromechanical closing systems, locking systems or
sensors with or without integrated electrical functions (MID) for
[0093] refrigerators, chest refrigerators, chest freezers [0094]
ovens, cookers, steam cookers [0095] dishwashing machines
Automotive Sector
[0096] Housings and/or holders with or without integrated
electrical functions (MID) in homogenous design or as a hybrid part
for [0097] controls/switches (e.g. for exterior mirror adjustment,
seat position adjustment, lighting, driving direction indicator)
[0098] interior sensors, e.g. for seat occupation [0099] exterior
sensors (e.g. for parking aids, ultrasonic or radar distance
meters) [0100] sensors in the engine space (e.g. vibration or
knocking sensors) [0101] interior and exterior lights [0102] motors
and/or drive elements in the interior and exterior area (e.g. for
seat comfort functions, exterior mirror adjustment, headlight
adjustment and/or tracking, curve light) [0103] monitoring and/or
control systems for vehicle drive (e.g. for media transport and/or
regulation of, for example, fuel, air, coolant, lubricant)
[0104] Mechanical functional elements and/or sensor housings with
or without integrated electrical functions (MID) for [0105] closing
systems, locks, pull-to systems, e.g. in the case of vehicle swivel
doors, sliding doors, engine space flaps or hoods, tailgates,
vehicle windows [0106] connectors for fluid lines, connectors in
the field of vehicle electrics and vehicle electronics
Mechanical Engineering
[0106] [0107] ISO standard parts and/or machine elements (e.g.
screws, nuts, bolts, wedges, shafts, gear wheels) in standard
dimensions or application-specific design or homogenous design
[0108] ISO standard parts and/or machine elements, such as, for
example, screws, nuts, bolts, wedges, shafts in standard dimensions
or application-specific design or as a hybrid part, certain
functional regions, such as, for example, force transmission
surfaces, sliding surfaces, decorative layer areas, may comprise
another compatible or incompatible material (for example for
targeted delamination, predetermined breaking point, force/torque
limitation) [0109] supports, stands, plinths for processing
machines, such as, for example, upright drilling machines, table
drilling machines, cutting machines or combination machines for
metal and/or wood processing [0110] insert parts, e.g. threaded
bushes [0111] self-tapping screws
Energy and Drive Technology Sector
[0111] [0112] frames, housings, support parts (substrate) and/or
fixing elements for solar cells with or without integrated
electrical functions (MID) in homogeneous design or as a hybrid
part [0113] tracking and/or adjusting elements (e.g. for bearings,
hinges, joints, drawbars, bumpers) for collectors [0114] pump
housings and/or valve housings with or without integrated
electrical functions (MID) in homogenous design or as a hybrid
part
Medical Equipment Sector
[0114] [0115] frames, housings, support parts with or without
integrated electrical functions (MID) in homogeneous design or as a
hybrid part for monitoring devices and/or equipment for supporting
vital functions [0116] disposable instruments, such as, for
example, scissors, clamps, forceps, knife handles in homogeneous
design or as a hybrid part [0117] constructions for short-term or
emergency fixing of fractures in homogeneous design or as a hybrid
part [0118] walking aids with or without integrated electrical
functions (MID) and/or sensors for load monitoring in homogeneous
design or as a hybrid part.
[0119] The following examples will explain the invention, without
limiting it.
EXAMPLES
[0120] In the examples and comparative examples (CE) the following
materials were used: [0121] PA Type A: Polyamide-12 with M.sub.n of
approximately 17,000 g/mol (.eta..sub.rel=1.66), EMS-CHEMIE AG,
Switzerland [0122] PA Type B: Polyamide MACM12 with
.eta..sub.rel=1.75, Tg=155.degree. C., .DELTA.H<1 J/g,
EMS-CHEMIE AG, Switzerland [0123] PA Type C: Polyamide-66 with
.eta..sub.rel=1.82, RADICI, Italy [0124] PA Type D: Polyamide 6I6T
(70:30), .eta..sub.rel=1.52, Tg=125.degree. C., .DELTA.H<1 J/g,
EMS-CHEMIE AG, Switzerland [0125] Glass fiber type A: NITTOBO
CSG3PA-820, 3 mm long, 28 .mu.m wide, 7 .mu.m thick, aminosilane
sizing, NITTO BOSEKI, Japan (flat glass fibers, according to the
invention) [0126] Glass fibers Type B: CS 7928, 4.5 mm long, 10
.mu.m diameter, BAYER AG, Germany (glass fibers with circular
cross-section, state of the art)
[0127] The molding materials of the compositions in Table 1 are
prepared on a twin-screw extruder from the film Werner &
Pfleiderer type ZSK25. The granuless PA12 are metered into the feed
zone. The glass fiber is metered into the polymer melt via a side
feeder 3 barrel unit before the die.
[0128] The barrel temperature has been set as an ascending
temperature profile up to 300.degree. C. At 150 to 200 rpm, 10 kg
throughput has been achieved. After cooling of the strands in a
water bath the granular properties were measured after granulation
and drying at 110.degree. C. for 24 h.
[0129] The test specimens have been produced on an Arburg injection
molding machine, wherein the cylinder temperatures were set to be
240.degree. C. to 300.degree. C. and a circumferential screw
velocity was set to 15 m/min. The molding temperature was chosen as
80-100.degree. C.
[0130] The measurements were performed according to the following
standards and at the following test specimens.
Tensile Modulus of Elasticity:
[0131] ISO 527 with a traction speed of 1 mm/min [0132] ISO tensile
bar, standard: ISO/CD 3167, type A1, 170.times.20/10.times.4 mm,
temperature 23.degree. C.
Breaking Strength and Elongation at Break:
[0132] [0133] ISO 527 with a speed of 5 mm/min [0134] ISO tensile
bar, standard: ISO/CD 3167, type A1, 170.times.20/10.times.4 mm,
temperature 23.degree. C.
[0135] Charpy Impact Strength: [0136] ISO 179/*eU [0137] ISO test
bar, standard: ISO/CD 3167, type B1, 80.times.10.times.4 mm,
temperature 23.degree. C. *1=not instrumented, 2=instrumented
Charpy Notch Impact Strength:
[0137] [0138] ISO 179/*eA [0139] ISO test bar, standard: ISO/CD
3167, type B1, 80.times.10.times.4, temperature 23.degree. C.
*1=not instrumented, 2=instrumented
Glass Transition Temperature (Tg), Melting Enthalpy (.DELTA.H)
[0139] [0140] ISO 11357-1/-2 [0141] Granules
[0142] The Differential Scanning calorimetry (DSC), was performed
with heating rate of 20.degree. C./min. The temperature is
specified for the Onset (Tg).
Relative Viscosity:
[0143] DIN EN ISO 307, in 0.5 wt-% m-cresol solution, temperature
20.degree. C.
MVR: (Melt Volume Rate)
[0143] [0144] According to ISO 1133 at 275.degree. C. and a load of
5 kg
Flow Length:
[0144] [0145] The flow length were determined using an Arburg
injection molding machine (type: ARBURG-ALLROUNDER 320-210-750).
Flow coils of the dimension 1.5 mm.times.10 mm were produced at a
melt temperature of 278.degree. C. (290.degree. C.) and a molding
temperature of 80.degree. C. (100.degree. C.).
Gloss:
[0145] [0146] Gloss measurement was performed according to ISO2813
with gloss meter Minolta Multi Gloss 268.
[0147] The glass fiber content is determined via TGA at the
granules by melting a sample of approximately 10 mg with a heating
rate of 20 K/min to 800.degree. C. From 600.degree. C. the flushing
medium nitrogen is substituted by air. The remaining amount
corresponds to the proportion of glass.
[0148] If is not otherwise indicated in the table, the specimens
are used in dry state. To do this, the specimens are stored in a
dry environment after the injection molding for at least 48 h at
room temperature.
TABLE-US-00001 TABLE 1 Example 1 CE1 2 CE2 3 CE3 Composition PA
type wt.-% 50 50 35 35 25 25 PA type B wt.-% 0 0 0 0 10 10 glass
fibers type A wt.-% 50 0 65 0 65 0 glass fibers type B wt.-% 0 50 0
65 0 65 Properties MVR cm.sup.3/10 77 65 45 15 25 17 (275.degree.
C./5 kg) min glass fiber wt.-% 49.3 49.6 64.6 64.9 65 64.9
percentage tensile strength at MPa 13200 12700 19800 19000 20500
19400 break tensile strength at MPa 180 165 213 183 220 188
elasticity elongation at % 3.3 4.2 2.5 3.5 2.7 3.4 break impact
strength kJ/m.sup.2 98 90 96 60 105 72 Charpy, 23.degree. C. notch
impact kJ/m.sup.2 29 22 32 17 34 18 strength, Charpy, 23.degree. C.
Glow below 85.degree. % 96 89 94 83 95 85 flow length mm 345 280
244 189 250 185 (278 C./80.degree. C.)
[0149] The following examples illustrate the advantages of
inventive molding materials in terms of improved transversal
strength and transversal rigidity.
[0150] To determine the rigidity and strength longitudinal and
transversal to the sprue, test specimens of the dimension
10.times.100.times.2 mm were used. They were both separated from
the middle of plates of the dimension 1001.times.00.times.2 mm
(with film-sprue respectively). The plates were made from the
molding materials of example 2 (flat glass fibers: according to the
invention) and CE2 (glass fibers with a round cross-section).
TABLE-US-00002 TABLE 2 Example 2a and comparative example CE2a
Example 2a CE2a tensile modulus elasticity, MPa 12900 12550
longitudinal tensile modulus of elasticity MPa 9170 6480
transversal ratio tensile modulus of elasticity 0.71 0.52
transversal/longitudinal tensile strength at break MPa 139 124
longitudinal tensile strength at break transversal MPa 70 58 ratio
tensile strength break 0.50 0.47 transversal/longitudinal
[0151] Compared to the molding materials with round glass fibers,
the inventive molding material (example 2a) shows an increase of
more than 40% in transversal rigidity and a 20% increase in
transversal strength.
TABLE-US-00003 TABLE 3 Example 4 and Comparative Example 4 Example
4 CE4 PA type C wt.-% 37.5 37.5 PA type D wt.-% 12.5 12.5 glass
fibers type A wt.-% 50 0 glass fibers type B wt.-% 0 50 MVR
(275.degree. C./5 kg) cm.sup.3/10 min 95 75 percentage of glass
fiber wt.-% 49.5 49.7 tensile modulus of elasticity, MPa 15870
13830 longitudinal tensile modulus of elasticity, MPa 9314 6920
transversal ratio tensile modulus of elasticity 0.58 0.50
transversal/longitudinal tensile strength at break MPa 204 184
longitudinal tensile strength at break transversal MPa 134 110
ratio tensile strength at break 0.66 0.58 transversal/longitudinal
impact strength, Charpy, 23.degree. C. kJ/m.sup.2 75 70 notch
impact strength, kJ/m.sup.2 25 17 Charpy, 23.degree. C. flow length
(mass temperature: mm 370 305 290.degree. C., molding temperature:
100.degree. C.) filling pressure during injection bar 1000 1300
molding (manufacture of test specimen) average fiber length in the
molding .mu.m 350 220 material (BIAX test specimen)
[0152] For the tensile test, special test specimens (BIAX,
published in Noss'Ovra staff magazine, December 2006, No 12, volume
29, EMS-CHEMIE AG) were used, which enable anisotropic measurement
of rigidity and strength.
[0153] It results from the comparison between example 4 (according
to the invention) and comparative example 4, that transversal
rigidity can be enhanced by more than 10% and cross-strength can be
enhanced by more than 20% via a combination of flat glass fibers
with the inventive low viscous polyamide molding material.
[0154] After incinerating the test specimens, the length
distribution of the glass fibers, and the average fiber length have
been determined. The inventive molding materials contained glass
fibers with significantly increased fiber length.
[0155] Production of the test specimens via injection molding shows
another advantage of the inventive molding materials, namely
significantly reduced filling pressure as compared to the usual
molding materials, which are reinforced with round glass fibers.
The combination of low viscous polyamides and flat glass fibers
enables the production of injection molded parts with a filling
pressure reduced by 20-30%.
[0156] Warpage was determined according to the following
specification:
[0157] Warpage Measurement (see FIGS. 1 to 7)
[0158] Warpage was determined at an injection molded body according
to FIG. 1. The sprue is done from the bottom in z direction. The
injection molded bodies were made at 280.degree. C. melt
temperature, and 80.degree. C. molding temperature.
[0159] The positions 1 to 12 were determined in x direction in
relation to point 4 and the positions 13 to 27 were determine in z
direction in relation to point 16 using a coordinate measuring
machine of the brand Tesa Validator 10 (see FIGS. 2 and 3).
[0160] These position deviations are plotted for the individual
positions. They are shown in FIGS. 4 to 7.
[0161] In the case of the injection molded body with flat glass
fibers, a noticeably more isotropic behavior regarding form
preservation and a significantly lower average warpage is observed
over all measuring points.
[0162] To further document the superior properties of the materials
presented here, comparative measurements were carried out for
systems only comprising component A but no component B as given in
Table 4. All relative viscosities given in Tables 4 and 5 are for
0.5 weight % solutions in m-cresol.
TABLE-US-00004 TABLE 4 Example 5 6 CE5 Composition Component A
(PA12) Weight % 34.825% 34.825% 34.825% EMS Product Grilamid L16
Grilamid L20 Grilamid L25 Rel. Viscosity 1.72 1.85 2.25 Component B
Weight % -- -- -- Additives Irganox 1010 (Ciba) Weight % 0.175
0.175 0.175 Glass Fiber CSG3PA-820 (Nittobo) Weight % 65 65 65
(axis ratio 4:1) Properties (dry) Flowability MVR 190 72 34
275.degree. C./21.6 kg [ml/10 min] Flowability Flow Length 240 200
180 280.degree. C./80.degree. C./ 1000 bar [mm] Suitability for
Grade + .largecircle. - Metallization* Notched Impact [kJ/m2] 24 21
20 Impact Charpy [kJ/m2] 85 79 50 Tensile Modulus [MPa] 19'200
18'500 18'500 Tensile Strength [MPa] 185 175 160 at Break
Elongation at Break [%] 2.5 2.9 2.3 Tensile Modulus [MPa] 16'300
15'500 15'000 longitudinal Tensile Strength at [MPa] 190 180 170
Break longitudinal Elongation at Break [%] 2.4 2.7 2.9 longitudinal
Tensile Modulus [MPa] 8'700 7'500 7'400 transversal Tensile
Strength [MPa] 108 107 103 transversal Elongation at Break [%] 3.0
3.4 4.0 transversal *"Suitability for Metallization" means the
absence of surface cloudiness (often described as orange-peel
effect) with increasing distance to the gate.
[0163] High-quality-looking metallic lacquers or piano lacquers
require the complete absence of any surface superstructure. This
also applies to an after treatment with NCVM (Non Conductive Vacuum
Metallization).
Grade:
[0164] + good surface quality; optimally qualified for
metallization [0165] o partial superstructure apparent; suitable to
only a limited extent for metallization [0166] - inadequate surface
quality; unsuitable for metallization
[0167] A low viscosity PA12 (component A) reinforced with 65 wt.-%
of flat glass fibers (component C) as given in example 5 is clearly
superior to a further example 6 based on medium viscosity PA12
which is again superior to a comparative example CE 5 from the
respective high viscosity PA12, each with exactly the same
reinforcement. The only exception is "elongation at break" which is
high for all examples but generally known to slightly increase with
viscosity.
[0168] To further document the superior properties of the materials
presented here, comparative measurements were carried out for
systems comprising component A as well as component B as given in
Table 5, namely for a mixture of polyamide PA66 (component A) and
low viscosity copolyamide PA6I/6T (component B) reinforced with 65
wt.-% of flat glass fibers.
TABLE-US-00005 TABLE 5 Example 7 8 CE6 CE7 Composition Component A
(PA66) Weight % 29.775 29.775 29.775 29.775 Product Name Radipol
A40 Radipol A45 Stabamid 31/A00S Radipol A105 (Manufacturer)
(Radici) (Radici) (Rhodia) (Radici) Rel. Viscosity 1.78 1.85 1.91
1.96 Component B Weight % 9.925 9.925 9.925 9.925 (PA6I/6T) Rel.
Viscosity 1.52 1.52 1.52 1.52 Grivory G21 (EMS) Additives Irganox
1098 (Ciba) Weight % 0.3 0.3 0.3 0.3 Hostanox PAR24 Weight % 0.1
0.1 0.1 0.1 (Clariant) Glass Fiber Weight % 60 60 60 60 CSG3PA-820
(Nittobo) (axis ratio 4:1) Properties (dry) Flowability Melt volume
87 76 65 41 rate 275.degree. C./21.6 kg [ml/10 min] Flowability
Flow Length 220 200 190 180 300.degree. C./100.degree. C./ 1000 bar
[mm] Suitability for Grade + + .largecircle. .largecircle.
Metallization* Notched Impact [kJ/m2] 12 12 11 13 Impact Charpy
[kJ/m2] 64 68 59 64 Tensile Modulus [MPa] 21'400 21'700 21'200
21'600 Tensile Strength [MPa] 255 260 250 260 at Break Elongation
at Break [%] 2.0 2.0 2.0 2.1 Tensile Modulus [MPa] 19'800 20'400
longitudinal Tensile Strength at [MPa] 240 245 Break longitudinal
Elongation at Break [%] 1.8 1.8 longitudinal Tensile Modulus [MPa]
12'900 13'000 transversal Tensile Strength [MPa] 129 130
transversal Elongation at Break [%] 1.4 1.3 transversal
"Suitability for Metallization" means the absence of surface
cloudiness (often described as orange-peel effect) with increasing
distance to the gate.
[0169] High-quality-looking metallic lacquers or piano lacquers
require the complete absence of any surface superstructure. This
also applies to an after treatment with NCVM (Non Conductive Vacuum
Metallization).
Grade:
[0170] + good surface quality; optimally qualified for
metallization [0171] o partial superstructure apparent; suitable to
only a limited extent for metallization [0172] - inadequate surface
quality; unsuitable for metallization
[0173] The mixture of polyamide PA66 (component A) and low
viscosity copolyamide PA6I/6T (component B) reinforced with 65
wt.-% of flat glass fibers (component C) shows constant mechanical
properties essentially independent of PA66 viscosity in the range
between 1.78 and 1.96. But low viscosity PA66 is necessary for
maximum flow length and surface quality (suitability for
metallization).
* * * * *